Top: diagram with the shape of the ionizing radiation field (energy units, normalized to the flux at the Lyman limit) assumed in CLOUDY to model the stellar emission (orange curve) and the AGN emission (black, red, and darkred curves, as described in the legend). For these representative curves we have assumed log(U) = − 2, solar metallicity, and a density of 10³ cm⁻³ in all cases. In the AGN models from Thomas et al. (2016), we identify with the same color (red or darkred) the family with a common E_peak, in which the parameter p_NT increases toward the top from the lighter to the darker line. The dashed shaded lines indicate the transmitted continuum. Bottom: zoom-in of the top panel in the energy range between 5 and 100 eV, but with a linear scale on the x-axis and the flux density f_ν (normalized to the flux density at the Lyman limit) on the y-axis. This version of the plot is inspired by Feltre et al. (2016). The area between the two AGN shapes of Thomas et al. (2016) with the same p_NT = 0.25 and varying E_peak (in the range 20 − 100 eV) is filled with a chequered red pattern.